Organic compounds

ABSTRACT

Alkyl-2-enoic acid esters of formula  
                 
 
wherein R 1 , R 2  and R 3  have the same meaning as described in the specification, their manufacture and their use in flavour and fragrance compositions.

This invention refers to new alkyl-2-enoic acid esters, theirmanufacture and their use in flavour and fragrance compositions.

The flavour and fragrance industry is always Interested in new compoundsthat may enhance, improve, or modify the aroma or flavour in foodstuffsand consumable materials.

Surprisingly, we found certain alkyl-2-enoic acid ester compoundsenhance, improve, or modify flavour notes, in particular fruity notes,e.g. blackberry and strawberry notes.

Accordingly, the present invention refers in one of its aspects to aflavour or fragrance composition comprising a compound of formula (I)

wherein R¹ is C₄, C₅, or C₆ linear or branched alkyl, e.g. n-butyl,sec-butyl, tert-butyl, n-pentyl, 3-methyl-butyl, 2-methyl-butyl,1-methyl-butyl, 1-ethyl-propyl,1,2-dimethyl-propyl, 2-ethylbutyl; and

R² and R³ are independently hydrogen, methyl or ethyl, with the provisothat a maximum of one of R² and R³ is hydrogen;

with the proviso that if R² is hydrogen and R³ is methyl, R¹ is notbutyl or 1,3-dimethylbutyl.

Particularly preferred compounds for use in compositions according tothe invention are butyl 3-ethylbutenoate, isobutyl 3-ethylbutenoate,pentyl 3-ethylbutenoate, 3-methylbutyl 3-methylpentenoate, 2-methylbutylpentenoate, 2-methylbutyl 3-methylbuteonate, 2-methylbutyl3-methylpentenoate, 2-methylbutyl 3-ethylpentenoate, 1-methylbutylbutenoate, 1-methylbutyl 3-methylpentenoate, 1-ethylpropyl3-methylbutenoate and 1-ethylpropyl 3-methylpentenoate.

Most preferred Is 2-methylbutyl 3-methylbutenoate.

Whereas some compounds of the formula (I) have been described in theliterature, others have not, and are novel. Thus, the invention providesin another aspect of the invention a compound of formula (I) selectedfrom the group of: chemical name R¹ R² R³ butyl 3-ethylbutenoate butylethyl methyl butyl 3-ethylpentenoate butyl ethyl ethyl isobutyl3-ethylbutenoate isobutyl ethyl methyl isobutyl 3-ethylpentenoateisobutyl ethyl ethyl sec-butyl 3-ethylpentenoate sec-butyl ethyl ethylpentyl pentenoate pentyl ethyl hydrogen pentyl 3-ethylbutenoate pentylethyl methyl pentyl 3-ethylpentenoate pentyl ethyl ethyl 3-methylbutylpentenoate 3-methylbutyl ethyl hydrogen 3-methylbutyl 3-methylpentenoate3-methylbutyl ethyl methyl 3-methylbutyl 3-ethylpentenoate 3-methylbutylethyl ethyl 2-methylbutyl pentenoate 2-methylbutyl ethyl hydrogen2-methylbutyl 3-methylbuteonate 2-methylbutyl methyl methyl2-methylbutyl 3-methylpentenoate 2-methylbutyl ethyl methyl2-methylbutyl 3-ethylpentenoate 2-methylbutyl ethyl ethyl 1-methylbutylbutenoate 1-methylbutyl methyl hydrogen 1-methylbutyl pentenoate1-methylbutyl ethyl hydrogen 1-methylbutyl 3-methylpentenoate1-methylbutyl ethyl methyl 1-methylbutyl 3-ethylpentenoate 1-methylbutylethyl ethyl 1-ethylpropyl butenoate 1-ethylpropyl methyl hydrogen1-ethylpropyl pentenoate 1-ethylpropyl ethyl hydrogen 1-ethylpropyl3-methylbutenoate 1-ethylpropyl methyl methyl 1-ethylpropyl3-methylpentenoate 1-ethylpropyl ethyl methyl 1-ethylpropyl3-ethylpentenoate 1-ethylpropyl ethyl ethyl

The compounds of formula (I) may comprise one or more chiral centres andas such may exist as a mixture of stereoisomers, or they may be resolvedas isomerically pure forms. Resolving stereoisomers adds to thecomplexity of manufacture and purification of these compounds and so itis preferred to use the. compounds as mixtures of their stereoisomerssimply for economic reasons. However, if it is desired to prepareindividual stereoisomers, this may be achieved according to methodsknown in the art, e.g. preparative HPLC and GC or by stereoselectivesyntheses.

In one embodiment, the compounds of formula (I) may be used In flavouredproducts and are useful in modifying, for example, fruity flavours. Theymay also be used in aromatic, herbal and spicy flavouring. Flavouredproducts for which the compounds of formula (I) are suitable are foodand beverages such as breakfast cereals, alcoholic and non-alcoholicbeverages, chewing gum, confections and frostings, fruit juices, frozendairy desserts and mixes, fruit and water ices, gelatins, puddings, hardcandy and cough drops, jams and jellies, commercial milk (whole andskim), milk products, processed fruits and fruit juices, soft candy,sweet sauces, toppings and syrups. This list of products is given by wayof illustration and is not to be regarded as being in any way limiting.

The compounds of the present invention may be used in flavoured productsalone or in combination with other flavour ingredients known to theperson skilled in the art.

In another embodiment, the compounds of formula (I) may be used infragrance applications, e.g. in any field of fine and functionaryperfumery, such as perfumes, household products, laundry products, bodycare products and cosmetics.

In flavour applications, the compounds of the formula (I) may be presentin consumables, e.g. a food, a beverage or a consumer healthcareproduct, in amounts ranging from 0.5 to 100 ppm, more preferably from 1to 50 ppm. When used in fragrance applications, compounds of the formula(I) can be employed in wide-ranging amounts depending upon the specificapplication, for example, from about 0.001 to about 10 weight percent.One application may be a fabric softener comprising about 0.001 to 0.05weight percent of the compound. Another application may be a perfume,i.e. an alcoholic solution, comprising about 0.1 to 10 weight percent ofthe compound. The preferred concentrations vary between about 0.1 and 5weight percent. However, these values should not be regarded as limitingon the present invention, since the experienced perfumer may alsoachieve effects with even lower concentrations or may create novelaccords with even higher amounts.

Accordingly, a further aspect of the present invention refers to amethod of improving, enhancing or modifying a flavoured or fragrancedproduct comprising the step of adding thereto an olfactory acceptableamount of a compound of formula (I).

The compounds of formula (I) may be synthesised from commonly-availablestarting materials by acidic catalyst esterification of carboxylic acidsor acid chlorides according to synthetic protocols known in the art.Examples of acidic catalyst are para-toluene sulfonic acid monohydrate,tartaric acid and H₂SO₄. Optically pure compounds of formula (I) andstereoisomer mixtures of a compound of formula (I) enriched in onestereoisomer may be synthesised by starting from optically pure alcohol,e.g. S-(−)-2-methylbutanol, or an stereoisomer mixture enriched in onestereoisomer alcohol respectively.

There now follows a series of non-limiting examples that illustrate theinvention.

EXAMPLE 1 2-Methylbutyl 3-methylbutenoate

At room temperature under nitrogen in a 500 ml flask, a mixture of 87.3g of 3,3-dimethylacrylic acid (0.85 mol) and 1 34.7 g ofDL-2-methyl-1-butanol (1.50 mol, 1.75 eq.) and 4.25 g of para-toluenesuflonic acid monohydrate (0.024 mol, 0.026 eq.) was treated with 100 mlheptane and then heated at reflux at 90° C. for 14 hours while 15.4 ml(0.85 mol) of H₂O was collected in a Dean-Stark trap. The result was anorange solution. The solution was extracted with MTBE/brine (2×350ml/200 ml brine). The organic layers were washed with NaHCO₃ (200 mlsaturated solution), brine (200 ml), dried over MgSO₄ and concentrated.205 g of a orange liquid was recovered, which was purified bydistillation over a 30 cm plate-column. 131.1 g of a colorless liquidwas recovered (bp 58° C./3.5 torr (4.7 bar) 90.5% yield).

¹H NMR: 5.69 (s, 1H), 3.93 (dq, 2H), 2.17 (s, 3H), 1.89 (s, 3H), 1.74(m, 1H), 1.44 (m, 1H), 1.20 (m, 1H), 0.91 (m, 6H). ¹³C NMR: 116, 68, 34,27, 26, 20, 16, 11. MS: 170 (M+), 100, 83, 70, 55, 43.

Taste description (4 ppm in water): fleshy, metallic, skinny, floral,complex, powdery, fatty.

Odour description: blackberry, peely, light tobacco with metallicaspects

EXAMPLE 2 Beverage with Blackberry Flavour

4 ppm 2-Methylbutyl 3-methylbutenoate was added to a beverage base (a)containing 0.15% by weight of the fruit flavour (b). Comparing theresulting composition with the aroma note of the starting beverage, thegreen, seedy and ionone notes were enhanced. The overall impressionshowed a nice complexing effect. By “complexing effect” is meant thatthe flavour profile is less simplistic, it rounds up the flavourprofile.

(a) Beverage Base weight % sugar 10.00 citric acid 0.15 water 89.85

(b) Composition of a Blackberry Flavour parts by weight 1/1000 water(deionized), 533.2000 propylene glycol 225.0000 ethyl alcohol 190 PRgrain 225.0000 blackberry essence 100x 10.0000 ethyl butyrate 2.2000ethyl pyruvate 1.1502 maltol 1.0000 raspberry ketone 0.5000 2-heptanol0.4000 hexanol 0.2160 2-methyl butyric acid 0.2133 cis-3-hexenyl acetate0.1944 acetaldehyde diethyl acetal 0.1485 methyl amyl ketone 0.13504-terpinenol 0.1134 alpha-terpineol crude 0.1080 ethyl isovalerate0.0999 ethyl caproate 0.0999 furaneol 0.0918 menthol 0.0405 hexylacetate 0.0378 trans-2-hexenal 0.0216 ionone 0.0108 dimethyl sulfide0.0081 menthyl acetate 0.0054 benzyl acetate 0.0027 ambrette seedabsolute 0.0027 total 1000.0000

EXAMPLE 3 Beverage with Strawberry Flavour

8 ppm 2-Methylbutyl 3-methylbutenoate was added to a beverage base (a)of Example 2 containing 0.20% by weight of the fruit flavour (c).Comparing the resulting composition with the aroma note of the startingbeverage, seediness, fattiness and red fruit character was increased,and almost gave a raspberry note to the strawberry profile.

(c) Composition of a Strawberry Flavour parts by weight 1/10002-methylbutyl isovalerate 5.00 ethyl butyrate 19.00 ethyl isovalerate2.00 cis-3-hexenol 15.00 furaneol 20% in propylene glycol 100.00 ethylcaproate 0.23 methyl-2-methyl butyrate 0.22 benzaldehyde 0.40delta-dodecalactone 0.30 gamma-decalactone 0.70 diacetyl, 10% intriacetin 0.17 acetic acid 0.03 butyric acid 0.08 propylene glycol856.87 total 1000.00

1. A flavour or fragrance composition comprising a compound of formula(I)

wherein R¹ is C₄ to C₆ linear or branched alkyl; and R² and R³ areindependently hydrogen, methyl or ethyl, with the proviso that a maximumof one of R² and R³ is hydrogen; with the proviso that if R² is hydrogenand R³ is methyl, R¹ is not butyl or 1,3-dimethylbutyl.
 2. A flavour orfragrance composition according to claim 1 comprising a compound offormula (I) selected from butyl 3-ethylbutenoate, isobutyl3-ethylbutenoate, pentyl 3-ethylbutenoate, 3-methylbutyl3-methylpentenoate, 2-methylbutyl pentenoate, 2-methylbutyl3-methylbuteonate, 2-methylbutyl 3-methylpentenoate, 2-methylbutyl3-ethylpentenoate, 1-methylbutyl butenoate, 1-methylbutyl3-methylpentenoate, 1-ethylpropyl 3-methylbutenoate and 1-ethylpropyl3-methylpentenoate.
 3. A flavoured product comprising a compound offormula (I) as defined in claim
 1. 4. A flavoured product according toclaim 3 comprising a compound of formula (I) in an amount ranging from0.5 ppm to 100 ppm.
 5. A flavoured product according to claim 3 selectedfrom a food, a beverage, pharmaceutical, oral hygiene product orhealthcare product.
 6. A fragranced product comprising a compound offormula (I) as defined in claim
 1. 7. A fragranced product according toclaim 6 wherein the fragranced product is a fine fragrance or perfumedproduct selected from a cosmetic, or a consumer healthcare or householdproduct.
 8. A method of improving, enhancing or modifying a flavoured orfragranced product comprising the step of adding thereto an olfactoryacceptable amount of a compound of formula (I) as defined in claim
 1. 9.A compound of formula (I)

wherein the groups R¹, R² and R³ are selected according to the followingtable: R¹ R² R³ butyl ethyl methyl butyl ethyl ethyl isobutyl ethylmethyl isobutyl ethyl ethyl sec-butyl ethyl ethyl pentyl ethyl hydrogenpentyl ethyl methyl pentyl ethyl ethyl 3-methylbutyl ethyl hydrogen3-methylbutyl ethyl methyl 3-methylbutyl ethyl ethyl 2-methylbutyl ethylhydrogen 2-methylbutyl methyl methyl 2-methylbutyl ethyl methyl2-methylbutyl ethyl ethyl 1-methylbutyl methyl hydrogen 1-methylbutylethyl hydrogen 1-methylbutyl ethyl methyl 1-methylbutyl ethyl ethyl1-ethylpropyl methyl hydrogen 1-ethylpropyl ethyl hydrogen 1-ethylpropylmethyl methyl 1-ethylpropyl ethyl methyl 1-ethylpropyl ethyl ethyl


10. The flavoured product according to claim 3 comprising a compound offormula (I) selected from butyl 3-ethylbutenoate, isobutyl3-ethylbutenoate, pentyl 3-ethylbutenoate, 3-methylbutyl3-methylpentenoate, 2-methylbutyl pentenoate, 2-methylbutyl3-methylbuteonate, 2-methylbutyl 3-methylpentenoate, 2-methylbutyl3-ethylpentenoate, 1-methylbutyl butenoate, 1-methylbutyl3-methylpentenoate, 1-ethylpropyl 3-methylbutenoate and 1-ethylpropyl3-methylpentenoate.
 11. The flavoured product according to claim 10comprising a compound of formula (I) in an amount ranging from 0.5 ppmto 100 ppm.
 12. The flavoured product according to claim 11 selectedfrom a food, a beverage, pharmaceutical, oral hygiene product orhealthcare product.
 13. The flavoured product according to claim 10selected from a food, a beverage, pharmaceutical, oral hygiene productor healthcare product.
 14. The fragranced product according to claim 6comprising a compound of formula (I) selected from butyl3-ethylbutenoate, isobutyl 3-ethylbutenoate, pentyl 3-ethylbutenoate,3-methylbutyl 3-methylpentenoate, 2-methylbutyl pentenoate,2-methylbutyl 3-methylbuteonate, 2-methylbutyl 3-methylpentenoate,2-methylbutyl 3-ethylpentenoate, 1-methylbutyl butenoate, 1-methylbutyl3-methylpentenoate, 1-ethylpropyl 3-methylbutenoate and 1-ethylpropyl3-methylpentenoate.
 15. The fragranced product according to claim 14wherein the fragranced product is a fine fragrance or perfumed productselected from a cosmetic, or a consumer healthcare or household product.16. The fragranced product according to claim 14 comprising a compoundof formula (I) in an amount ranging from 0.001-10 weight %.
 17. Thefragranced product according to claim 6 comprising a compound of formula(I) in an amount ranging from 0.001-10 weight %.
 18. The methodaccording to claim 8 wherein the flavoured or fragranced productcomprises a compound of formula (I) selected from butyl3-ethylbutenoate, isobutyl 3-ethylbutenoate, pentyl 3-ethylbutenoate,3-methylbutyl 3-methylpentenoate, 2-methylbutyl pentenoate,2-methylbutyl 3-methylbuteonate, 2-methylbutyl 3-methylpentenoate,2-methylbutyl 3-ethylpentenoate, 1-methylbutyl butenoate, 1-methylbutyl3-methylpentenoate, 1-ethylpropyl 3-methylbutenoate and 1-ethylpropyl3-methylpentenoate.